This project involves studies on the chemical structure and physicochemical characteristics of certain natural biopolymeric materials and their synthetic analogs with the aim of relating the resulting structural information to their biological mode of action. Current emphasis is focused on proteins that play a role in cell growth regulation, cell transformation or differentiation. Emphasis is placed in applying the modern methods of mass spectrometry, chromatography and of chemical methods of sequencing. Projects include: (1) Development of methods and application of fast atom bombardment mass spectrometry. Systematic investigation of 9 N-terminal pyroglutamate-blocked peptides demonstrated structurally characteristic spectral features, and also indicated that C and Z type of amino acid sequence-determining ions predominate in the spectra. Bromine-containing group-specific labeling reagents were found to be useful in enhancing the sequence specific ions in the spectra in general. Spectral measurements on several synthetic transforming growth factor-alpha polypeptide segments secured the monomeric/oligomeric status and the oxidation state of the thiol groups present in the molecules. (2) Structural studies on gamma-glutamyl transpeptidase, a hepatic tumor marker enzyme. Amino acid sequencing studies and two-dimensional gel electrophoretic studies have been completed to the extent that the sequence information could be compared to recent DNA cloning data by others. Our electrophoretic isozyme analysis results offer a method of general applicability to inter-tissue and inter-species comparative studies.